Immune systems of babies who develop food allergies are 'primed' for them by the time they are born, says new research

Babies with hyperactive immune cells at birth are more likely to develop food allergies in early life, new Australian research has found.

The discovery could lead to future treatments to prevent childhood food allergies which have increased dramatically in recent decades.

The research by Dr Yuxia Zhang and Professor Len Harrison from the Walter and Eliza Hall Institute, and Associate Professor Peter Vuillermin from Barwon Health, Deakin University and the Murdoch Childrens Research Institute, is published in the journal Science Translational Medicine.

Prof Harrison told AAP the findings of the study of more than 1000 Victorian babies were important and gave very clear results.

"We found a link between children who had hyperactive immune cells at birth and the development of allergies to milk, eggs, peanuts, wheat and other common foods in their first years of life," Prof Harrison said.

Those with activated immune cells at birth, detected in the babies' cord blood, were "much more likely" to have the food allergy, raising the next question of the reason for this.
"In at-risk babies, immune cells called monocytes were activated before or during birth," said Dr Zhang.

"Signals from these cells encouraged the development of immune responses by specialised immune cells called T cells that were predisposed to cause allergic reactions to some foods."

Prof Vuillermin said they had shown that the immune systems of babies who develop food allergy are in a sense "primed" for allergic disease by the time they are born.

Describing the hyperactive cells as a "signature of risk" of allergy, Prof Harrison said researchers would now try to identify why the babies had the cells.

"Are the immune cells inherently activated because of the baby's genes or do they become activated at the time of birth or earlier in pregnancy, and how?" he said.

"This study really emphasises how critical it is to look at pregnancy and early life to really understand why chronic immune and inflammatory disorders such as allergies develop in childhood and later."